black swan

Definition

Colloquial term for any extremely rare event. The term was popularized by a book by Nassim Nicholas Taleb, entitled "The Black Swan", and was based on a previous belief (now a misconception) that all swans were white and that black swans did not exist. The term is frequently used in the finance and investingsectors to denote an event that is unexpected, and impossible to accurately predict.

Use black swan in a sentence

“
It was a black swan and that meant that it was rare and we would probably never see it again, for the rest of our lives.
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“
When Bernie Madoff was convicted of running a ponzi scheme and bilking millions of dollars from his investors, one of his most loyal clients was in utter disbelief and thought the whole event akin to a black swan.
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